A communication system is arranged for the provision of communication connections between two or more entities such as user terminal equipment and/or other nodes associated with the system. One of these entities may be a service provider. The communication system may comprise, for example, communication of voice, electronic mail and text messages, multimedia messages, data and so on.
The communication system may use a wireless interface for the user terminals. An example of a system using wireless communication is a public land mobile network (PLMN). A communication system typically operates in accordance with a given standard specification which sets out what the various elements of the system are permitted to do and how that should be achieved. For example, the standard specification may define if the user equipment or terminal is provided with a circuit switch (CS) service or a packet switched (PS) service or both. Communication protocols and/or parameters which need to be used for the communication are also typically defined. For example, the manner in which communication is implemented between the user and the elements of the communication network is usually based on a predetermined communication protocol.
Examples of the different standards and/or specifications for wireless communications include GSM (global system for mobile communications), AMPS. (American mobile phone system), DAMPS (digital amps) various GSM based systems such as GPRS (general packet radio service) as well as so-called third generation standards including cdma2000 (code division multiple access2000), UMTS (universal mobile telecommunication system), IMT2000 (international mobile telecommunication system 2000) and so on.
In known wireless cellular communication systems, the area covered by the network is divided into cells which may or may not be overlapping. Associated with each cell is a base station which is arranged to communicate with mobile stations or other suitable user equipment in the cell associated with a base station. In some standards, the base station is referred to as a node B. However, in this document, the term base station will be used to refer to all such entities.
The base station is connected to and controlled by a controller entity. For example, in the UMTS network a base station is connected to and controlled by a node referred to as a Radio Network Controller (RNC). Again, similar nodes may be provided in different standards and may be referred to by different terms. In this document, the term radio network controller is intended to cover all such systems. The RNC node may in turn be connected to and controlled by a mobile switching centre (MSC), a serving GPRS support node (SGSN) or similar facility.
As part of the third generation standard, a new service called the multicast broadcast multimedia service (MBMS) has been proposed. This is a unidirectional point-to-multipoint service in which data is transmitted from a single source entity to a group of users in a specific area. The MBMS has two modes: the broadcast mode and the multicast mode. When using MBMS, all group members in an area may receive the same data over a common radio channel.